This wire set contains yellow ignition wires featuring a silicone inner core which is rated up to 600-degrees F. These wires provide increased fire power to the spark plugs and they eliminate radio frequency interference. They are a must when using a multi-spark discharge ignition system, electronic ignitions, and on-board computer systems. They have 90-degree spark plug boots, vibration-proof double spring locking spark plug terminals, and do not require sleeving.